Home Improvement Questions? Ask a Handyman for Answers
Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
Is the bearing or fitting around the black gear, where it goes into the housing of the opener, loose or damaged-looking in any way?
If so, then that degree of damage would probably be fairly expensive to repair, possibly more than the cost of simple replacement.
If not... then you might doubtfull have a case of 'dropped chain' between the two. Look around on the floor for such a short length of dropped chain.